Apparatus for the manufacture of transposed multiple strip conductor



Dec. 20, 1966 R. HINDS 3,292,356

APPARATUS FOR THE MANUFACTURE OF TRANSPOSED MULTIPLE STRIP CONDUCTOR Filed Dec. 4, 1963 4 Sheets-Sheet 1 Dec. 20, 1966 HlNDs 3,292,356

- APPARATUS FOR THE MANUFACTURE OF TRANSPOSED MULTIPLE STRIP CONDUCTOR Filed Dec. 4, 1963 4 Sheets-Sheet 2 Inventor Dec. 20, 1966 R. HINDS APPARATUS FOR THE MANUFACTURE OF TRANSPOSED MULTI PLE STRI P CONDUCTOR 4 Sheets-Sheet 5 Filed Dec. 4, 1963 lnvenfor Quad B WU V- Mm Dec. 20, 1966 R. HINDS APPARATUS FOR THE MANUFACTURE OF TRANSPOSED MULTIPLE STRIP CONDUCTOR 4 Sheets-Sheet 4 Filed Dec. 4, 1965 United States Patent 3,292,356 APPARATUS FOR THE MANUFACTURE OF TRANSPOSED MULTIPLE STRIP CON- DUCTOR Ronald Hinds, Stockton Heath, England, assignor to British Insulated Callenders Cables Limited, London, England, a British company Filed Dec. 4, 1963, Ser. No. 327,968 Claims priority, application Great Britain, Dec. 7, 1962,

46,272/ 62 11 Claims. (Cl. 5759) This invention relates to stranding machines for the manufacture of a known type of transposed multiple strip conductor of substantially rectangular cross-section, that is to say to the manufacture of conductors built up of a plurality of wires of rectangular or approximately rectangular cross-section grouped together to form a composite conductor of substantially rectangular form in which each component wire of the group, or, in the case of a conductor comprising a core wire or group of wires and an outer group of wires, of at least the outer group, changes step by step along the length of the conductor so that each wire occupies every position in its group in turn.

The manufacture of such transposed multiple strip conductor usually involves the use of a stranding machine in which the bobbins carrying the supplies of wire are mounted in a revolving cage or on a revolving disc or otherwise caused to move in a circular orbit round the axis of a forming or closing die into which the wires are led and from which they are drawn off by a capstan or other suitable form of haul-off device. While the bobbins are so orbiting their axes are held parallel to a fixed plane (generally a horizontal plane) containing the machine axis and the wires, .instead of taking a true helical path as in the case of the Wires of a circular conductor built up of round wires, each travel round the conductor axis in a path comprising a succession of short straight portions which are connected by fairly sharp bends which are formed by means of a transposing head. In such a machine it is desirable to ensure that, as the wires converge towards and enter the transposing head, they are correctly positioned, that is to say, where the strip is wider than it is thick, the longer sides of the cross-section are substantially parallel to the longer sides of its cross-section in the transposing head.

A positioning head for ensuring that this takes place comprises a rotor adapted to be mounted on the front end of and driven by the shaft of the cage or equivalent device on or in which are mounted the supply bobbins carrying the non-circular wire. The rotor has a peripheral flange provided with a number of bores whose axes lie in planes containing the axis of the head but are inclined to it. These bores, which are preferably hushed and uniformly distributed around the circumference of the flange, each house a tube which is rotatable in the bore and carries a die of a size and shape conforming with the cross-sectional size and shape of the wire to be positioned. In order that the major transverse axis of the positioning die may remain parallel to a given line as the head is rotated about the machine axis, each die-supporting tube is driven in rotation about its axis at the same angular speed as, but in the opposite sense to, the head itself.

Where the conductors pass from the cage or its equivalent and change their direction of travel so as to converge towards the closing die and, if used, the positioning head, it is necessary to provide some guiding device. For this purpose pairs of rolls mutually co-operating to provide .between them an opening corresponding in size and shape to the rectangular cross-section of the wire and driven in rotation about the axis of the opening between the rolls at the same angular speed as but in the opposite direction to the rotating cage or its equivalent would appear to be most suitable. We have found, however, that when roll deflecting guides of a form corresponding in size and shape to the cross-section of the wire are used, the wire is given a permanent bend as it passes from the deflector roll to travel along its convergent path towards the machine axis. This imparts a waviness to the strip which is especially noticeable in the case of the larger sizes of strip in use.

It is an object of this invention to provide for a stranding machine for the manufacture of transposed multiple strip conductor a bobbin planeting device having improved means for guiding the strips at the places where, having left their respective bobbins, they converge towards the closing die.

In accordance with the present invention these guiding means are arranged in the path of the strips between the bobbins and the transposing device and each comprise a guide having for the passage of a single strip a throated aperture of which the throat is of rectangular cross-section and has a width such as to allow free passage of the strip and a length at least several times that of the width of the strip, and means for rotating this die about an axis coincident with or substantially parallel with its own axis at the same angular speed as but in the reverse direction to the angular speed of the bobbin planeting device, so as to maintain the major transverse axis of each die aperture substantially parallel with the bobbin axis and hence with the major transverse axis of the cross-section of the strip as it passes through the transposing device. The transposing device may simply be a transposing head or may be a transposing head associated with a device, such as a positioning head, which positively guides the strips towards the transposing head.

By the use of strip guiding means in accordance with the present invention the angular change in direction of travel of the strip at the guiding means is very considerably reduced at the time when bending is mainly in the plane of the major axis of the cross-section of the strip, i.e. in the 3:00 oclock and 9:00 oclock positions of the strip in the case Where that major transverse axis is horizontal, the reduction being due to freedom of the strip to move from one end of the transversely elongated guide aperture to the other as the die orbits from the 3:00 oclock to the 9:00 oclock position and vice versa and/or as the point at which the strip leaves its supply bobbin changes from one end of the bobbin to the other. As a result waviness in the strip is substantially reduced or even eliminated.

Although we consider it to be preferably to apply the invention to a bobbin-planeting device of the back plate type, it may be applied to a bobbin-carrying device of the cage type in which each bobbin cradle is supported at its front as well as at its rear end by front and rear trunnions turning in hearings in front and rear rotary discs. In this latter case however, the front trunnion must be of much larger diameter than normal to accommodate the rectangular guiding die or to allow the strip room to move from side to side in such a die mounted on the front end of the trunnion.

When the bobbin-planeting device is of the back plate type, the ratio between the width of strip and the length of the rectangular throat of the guide is preferably such that at the maximum angular change of direction (which will occur when the bobbin from which a given strip is being drawn off is in the 3:00 oclock or 6:00 oclock position and the strip is leaving that end of its bobbin that at that moment lies nearest the axis of planetation) the inner end of the guide aperture is such that the strip just clears the rim of the inner flange of its bobbin. In other words the aperture is of a maximum length consistent with its preventing the strip from coming into contact with the bobbin flanges.

A strip stranding machine in accordance with the present invention will hereinafter be described ,by way of example with reference to the accompanying drawings in which- FIGURE 1 is an end elevation of part of the bobbin planetin'g device,

FIGURE 2 is a section on lines -IIII of FIGURE 1,

FIGURE 3 is a plan of a bobbin carrier, and

FIGURE 4 is a side elevation of the strip stranding machine.

The bobbin planeting device comprises a hollow back plate 1 and a plurality of bobbin cradles 2 each comprising a supporting shaft 3 rotatably supported in a bearing 4 in the back plate and carrying at its front end, which overhangs the bearing, a U-shape-d bracket 5 in the limbs of which are bearings 6 and 7 for the ends of a bobbin-supporting spindle 8. The two limbs carry arms 9 and 10 which extend, forwardly of the bobbin 11, to carry at their extremities a strip guide 12 of rectangular cross-section. On the rear end of the shaft 3 is a crank 13 directly coupled to a ring 14, or coupled to the ring 14 by a link 15, to enable the bobbin carrier to be given back rotation by one of the well known arrangements to maintain the cradles and their'bobbins horizontal. The back plate 1 is mounted on a hollow shaft 16 supported in bearings 17.

The guide 12 is formed from two lengths 18 and 19 of strip steel of D-section maintained in spaced parallel relationship with their convex surfaces facing one another, by welding their ends to end blocks 20 and 21 whose faces forming the end walls of the guide aperture are rounded olf in the same way as the top and bottom walls of the guide. The length of the rectangular throat of the guideis less than the width between the internal faces of flanges 22 of the bobbin 11 mounted in the carrier. The guide is mounted by screwing the ends of the arms 9 and 10 to the end blocks 20 and 21 of the guide, the arms converging as their extremities are approached to meet these end blocks.

In FIGURES '1 and 2. strips 23 are shown passing through a number of guides 12 from bobbins 11, under conditions in which the bobbins are almost empty. FIG- URE 2 shows as dotted lines 24 the paths taken by the strips 23 when the bobbins are full. FIGURE 4 shows the paths of three strips 23 from full bobbins 11, through a positioning head'25 to a transposing head 26, both of which heads are driven by an electric motor 27 which also drives the back plate 1 through shafts 28 and 29 and a belt drive 30.

The back plate 1 rotates in an anti-clockwise direction, as seen in FIGURE 1, and in general the strip 23 will move in an anti-clockwise direction around the boundary of the throat of each guide 12. Referring to FIGURE 1, when the guide is in the 12:00 oclock position the strip will generally lie against the middle of the lower boundary of the throat of the guide and as the die moves to the 9:00 oclock position the strip will move towards the right hand boundary and then rise up this boundary to the upper boundary of the throat. As the guide moves to the 6:00 oclock position the strip will move to the middle of the upper boundary'and as the guide moves from the 6:00 oclock position towards the 3:00 oclock position the strip will move to the left hand end of the upper boundary. As the guide passes through the 3:00 oclock position the strip will move to the lower boundary of the throat and as the guide moves towards the 12:00 oclock position the strip will move along the lower boundary reaching the centre of this boundary again in the 12:00 oclock position.

It is emphasised that this is only the general pattern of the movement of the strips in the guide; superimposed on this pattern will be variations caused by the varying amount of strip on the bobbin and the varying position 41 along the axis of the bobbin from which the strip leaves the bobbin.

Each guide is made with an aperture of the maximum possible length in order that the strip can adopt as natural. a path as possible between the bobbin and the transposing head (or positioning head if used). The width of the guide aperture is not of such importance since the upper. j and lower boundaries do not play a major part'ln the,

I guidance of the strip, although it is preferable thatthe guide should not be so narrow that the strip can bear.

against both the upper and lower boundaries of the aperture simultaneously, nor so wide that the strip never makes contact with these boundaries. In other words the preferred width of the aperture is such that, except when the strip is moving from the lower boundary towards the upper boundary or vice versa, it bears against one of these boundaries.

It will be appreciated that the maximum length of the rectangular throat of each guide will depend not only upon the width between flanges of its associated bobbin but also upon radius at which the bobbin cradle planets about the machine axis and also upon the distance between the guide and the axis of the bobbin when mounted in its cradle. In the case of a bobbin-planeting device of the back plate type in which the outer ring of bobbincradles has a pitch radius of 44.5", the bobbin has a flange to flange width of 11" and the throat of the guide is 20" from the axis of the bobbin when mounted in its cradle, an appropriate length for the rectangular throat of the guide is 8". An appropriate width of the aperture to receive 6" thick strip is '1 /2". Where an inner ring of bobbin cradles is mounted on the same back plate, guides having the same size of aperture may be used, in which case the bending of the strip when in the 9:00 oclock. and 3:00 oclock positions will be less because of the reduced angle of approach of the strip towards the closing Appropriate sizes of aperture for other sizes and placings of bobbins may readily be calculated by the. designer, bearing in mind that the maximum length of die.

throat, consistent with the practical limitations referred to, should always be used.

What I claim as my invention is:

1. In a stranding machine for the manufacture of transposed multiple strip conductor of substantially rectangular cross-section comprising a transposing device and a bobbin planeting device for supporting a plurality of bobbins of strip, a plurality of guiding means, one for guiding 63.6111

strip in its path between one of the bobbins and the transposing device, each comprising a guide having a throated aperture, of which the throat is of rectangular cross-section and has a width such as to allow free passage of the strip and a length at least several times that of the width of the strip, and means for moving this guide with the bobbin about the machine axis while maintaining major transverse axis of its aperture substantially parallel with the bobbin axis and hence with the major transverse axis of the cross-section of the strip as it passes through the transposing device.

2. A stranding machine as claimed in claim 1, in which each guide is formed from two parallel members having convex facing surfaces and two end members having convex facing surfaces.

3. In a stranding machine for the manufacture of.

transposed multiple strip conductor of substantially rectangular cross-section comprising a transposing head, a

comprising a guide having a throated aperture, of which the throat is of rectangular cross-section and has a width such as to allow free passage of the strip and a length at least several times that of the width of the strip, and

means for moving this guide with the bobbin about the machine axis while maintaining the major transverse axis of its aperture substantially parallel with the bobbin axis and hence with the major transverse axis of the crosssection of the strip as it passes through the positioning head.

4. A stranding machine as claimed in claim 3, in which each guide is formed from two parallel members having convex facing surfaces and two end members having convex facing surfaces.

5. In a stranding machine for the manufacture of transposed multiple strip conductor of substantially rectangular cross-section comprising a transposing device and a bobbin planeting device of the back plate type for supporting a plurality of bobbins, a plurality of guiding means, one for guiding each strip in its path between one of the bobbins and the transposing device, each comprising a guide having a throated aperture of which the throat is of rectangular cross-section and has a width such as to allow free passage of the strip and a maximum length consistent with its preventing the strip from coming into contact with the bobbin flanges, and means for moving this guide with the bobbin about the machine axis while maintaining the major transverse axis of its aperture substantially parallel with the bobbin axis and hence with the major transverse axis of the crosssection of the strip as it passes through the transposing device.

6. A stranding machine as claimed in claim 5, in which each guide is formed from two parallel members having convex facing surfaces and two end members having convex facing surfaces.

7. In a stranding machine for the manufacture of transposed multiple strip conductor of substantially rectangular cross-section comprising a transposing device and a bobbin planeting device of the back plate type provided with a plurality of cradles each for supporting a bobbin of tape, a plurality of guiding means, one for guiding each strip in its path between one of the bobbins and the transposing device, each comprising a guide having a throated aperture of which the threat is of rectangular cross-section and has a width such as to allow free passage of the strip and a length at least several times that of the width of the strip, so mounted on the bobbin cradle as to rotate with the cradle about the machine axis with the major transverse axis of the guide aperture substantially parallel with the bobbin axis and hence with the major transverse axis of the cross-section of the strip as .it passes through the transposing device.

8. A stranding machine as claimed in claim 7, in which each guide is formed from two parallel members having convex facing surfaces and two end members having convex facing surfaces.

9. A stranding machine as claimedin claim 7, comprising a pair of arms between which each guide is mounted projecting from each bobbin cradle, one on each side of the bobbin and substantially in the plane of the bobbin axis.

10. A stranding machine as claimed in claim 9, in which the bobbin cradles are U-shaped and the bobbins are mounted between the limbs of the cradles, and in which the arms project from and substantially in the common plane of the limbs of the U-shaped cradles.

11. A stranding machine as claimed in claim 9, in which each guide is formed from two parallel rods having convex facing surfaces supported between two end blocks having convex facing surfaces and themselves supported by said arms.

References Cited by the Examiner UNITED STATES PATENTS 288,677 1883 Stevenson 5759 2,105,338 1/1938 Sunderland 57l6l X 2,234,996 3/1941 Welch et al. 5759 2,249,509 7/1941 Welch et al. 5759 X 

1. IN A STRANDING MACHINE FOR THE MANUFACTURE OF TRANSPOSED MULTIPLE STRIP CONDUCTOR OF SUBSTANTIALLY RECTANGULAR CROSS-SECTION COMPRISING A TRANSPOSING DEVICE AND A BOBBIN PLANETING DEVICE FOR SUPPORTING A PLURALITY OF BOBBINS OF STRIP, A PLURALITY OF GUIDING MEANS, ONE FOR GUIDING EACH STRIP IN ITS PATH BETWEEN ONE OF THE BOBBINS AND THE TRANSPOSING DEVICE, EACH COMPRISING A GUIDE HAVING A THROATED APERTURE, OF WHICH THE THROAT IS OF RECTANGULAR CROSS-SECTION AND HAS A WIDTH SUCH AS TO ALLOW FREE PASSAGE OF THE STRIP AND A LENGTH AT LEAST SEVERAL TIMES THAT OF THE WIDTH OF THE STRIP, AND MEANS FOR MOVING THIS GUIDE WITH THE BOBBIN ABOUT THE MACHINE AXIS WHILE MAINTAINING MAJOR TRANSVERSE AXIS OF ITS APERTURE SUBSTANTIALLY PARALLEL WITH THE BOBBIN AXIS HENCE WITH THE MAJOR TRANSVERSE AXIS OF THE CROSS-SECTION OF THE STRIP AS IT PASSES THROUGH THE TRANSPOSING DEVICE. 